Li Yao, Gao Huilin, Allen George H, Zhang Zhe
Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX 77843 USA.
Department of Geography, Texas A&M University, College Station, TX77843 USA.
IEEE J Sel Top Appl Earth Obs Remote Sens. 2021;14:2249-2257. doi: 10.1109/jstars.2021.3051103. Epub 2021 Jan 12.
Area-volume-elevation (AVE) curves are critical for reservoir operation rules. However, such curves are not publicly available for most global reservoirs. Here, we present a framework to derive reservoir AVE curves from TanDEM-X data, using Lake Mead (~600 km) as an example. First, the maximum water extent from 1984 to 2018-provided by the global surface water (GSW) dataset-was used as a mask to obtain the TanDEM-X data. Then, the TanDEM-X water indication mask (WAM) was applied to the extracted TanDEM-X data to obtain the visible bathymetry, which represents the topography between the maximum extent (according to GSW) and the water extent from WAM. Last, the AVE curve was generated by integrating the volume values from the top to bottom layers. TanDEM-X also captures the elevation values of the transitional waters, which are defined as the difference between the highest and lowest water levels. The transitional waters were obtained by thresholding amplitude and coherence images, and their elevations were then added to the visible bathymetry to extend the AVE curves with an elevation range extending from 344-369 m to 341-369 m. Validation results against lidar survey values suggest a high-accuracy of elevation-area (E-A) relationships with values of >0.99 and NRMSE values from 2.11% to 2.45%, and elevation-volume (E-V) relationships with values of 1 and NRMSE values from 1.11% to 1.29%. Results also show that TanDEM-X data can capture the interannual variations due to multiple acquisitions, and that the elevation measurements for the lake shore areas are reliable.
面积-体积-高程（AVE）曲线对于水库运行规则至关重要。然而，对于全球大多数水库而言，此类曲线并非公开可得。在此，我们以米德湖（约600千米）为例，提出一个从TanDEM-X数据推导水库AVE曲线的框架。首先，将全球地表水（GSW）数据集提供的1984年至2018年的最大水域范围用作掩码，以获取TanDEM-X数据。然后，将TanDEM-X水指示掩码（WAM）应用于提取的TanDEM-X数据，以获得可见水深数据，该数据代表了最大范围（根据GSW）与WAM水域范围之间的地形。最后，通过对从上到下各层的体积值进行积分生成AVE曲线。TanDEM-X还捕获了过渡水域的高程值，过渡水域定义为最高和最低水位之间的差值。通过对振幅和相干图像进行阈值处理获得过渡水域，然后将其高程添加到可见水深数据中，从而将AVE曲线的高程范围从344 - 369米扩展到341 - 369米。与激光雷达测量值的验证结果表明，高程-面积（E-A）关系具有高精度，相关系数值>0.99，归一化均方根误差（NRMSE）值在2.11%至2.45%之间；高程-体积（E-V）关系也具有高精度，相关系数值为1，NRMSE值在1.11%至1.29%之间。结果还表明，TanDEM-X数据能够捕捉由于多次采集而产生的年际变化，并且湖岸地区的高程测量是可靠的。
